Gun laws in the United States are found in a number of state and federal statutes. These laws regulate the manufacture, trade, possession, transfer, record keeping, transport, and destruction of firearms, ammunition, and firearms accessories. They are enforced by state agencies and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).

Federal Firearms Act of 1938 ("FFA"): Requires that gun manufacturers, importers, and persons in the business of selling firearms have a Federal Firearms License (FFL). Prohibits the transfer of firearms to certain classes of persons, such as convicted felons.

Firearm Owners Protection Act ("FOPA") (1986): Revised and partially repealed the Gun Control Act of 1968. Prohibited the sale to civilians of automatic firearms manufactured after the date of the law's passage. Required ATF approval of transfers of automatic firearms.

Undetectable Firearms Act (1988): Effectively criminalizes, with a few exceptions, the manufacture, importation, sale, shipment, delivery, possession, transfer, or receipt of firearms with less than 3.7 oz of metal content.

Gun-Free School Zones Act (1990): Prohibits unauthorized individuals from knowingly possessing a firearm at a place that the individual knows, or has reasonable cause to believe, is a school zone.

Fugitives, those convicted of a felony with a sentence exceeding 2 years, or 2 year for a misdemeanor, past or present, and those who were involuntarily admitted to a mental facility are prohibited from purchasing a firearm. Forty-four states have a provision in their state constitutions similar to the Second Amendment to the United States Constitution, which protects the right to keep and bear arms. The exceptions are California, Iowa, Maryland, Minnesota, New Jersey, and New York. In New York, however, the statutory civil rights laws contain a provision virtually identical to the Second Amendment.[4][5] Additionally, the U.S. Supreme Court held in McDonald v. Chicago that the protections of the Second Amendment to keep and bear arms for self-defense in one's home apply against state governments and their political subdivisions.[6]

An individual right to own a gun for personal use was affirmed in the landmark District of Columbia v. Heller decision in 2008, which overturned a handgun ban in the Federal District of Columbia.[7] In the Heller decision, the court's majority opinion said that the Second Amendment protects "the right of law-abiding, responsible citizens to use arms in defense of hearth and home."

However, in delivering the majority opinion, Supreme Court Justice Antonin Scalia wrote on the Second Amendment not being an unlimited right:

Like most rights, the Second Amendment right is not unlimited. It is not a right to keep and carry any weapon whatsoever in any manner whatsoever and for whatever purpose: For example, concealed weapons prohibitions have been upheld under the Amendment or state analogues. The Court's opinion should not be taken to cast doubt on longstanding prohibitions on the possession of firearms by felons and the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, or laws imposing conditions and qualifications on the commercial sale of arms.[8][9]

The four dissenting justices argued that the majority had broken prior precedent on the Second Amendment,[10] and took the position that the amendment refers to an individual right, but in the context of militia service.[11][12][13][14]

The Supreme Court has not ruled on whether the Second Amendment protects the right to carry guns in public for self-defense.[16]Federal appeals courts have issued conflicting rulings on this point. For example, the United States Court of Appeals for the Seventh Circuit ruled in 2012 that it does, saying, "The Supreme Court has decided that the amendment confers a right to bear arms for self-defense, which is as important outside the home as inside."[17] However, the Tenth Circuit Court ruled in 2013 that it does not, saying, "In light of our nation's extensive practice of restricting citizen's freedom to carry firearms in a concealed manner, we hold that this activity does not fall within the scope of the Second Amendment's protections."[18] More recently, the Ninth Circuit Court ruled in its 2016 decision Peruta v. San Diego County that the Second Amendment does not guarantee the right of gun owners to carry concealed firearms in public.[19]

admitted into the United States for lawful hunting or sporting purposes

possesses a lawful hunting license or permit issued by any US state

an official representative of a foreign government who is accredited to the United States Government or the Government's mission to an international organization having its headquarters in the United States or is en route to or from another country to which that alien is accredited

an official of a foreign government or a distinguished foreign visitor who has been so designated by the Department of State

a foreign law enforcement officer of a friendly foreign government entering the United States on official law enforcement business

has received a waiver from the United States Attorney General as long as the waiver petition shows this would be in the interests of justice and would not jeopardize the public safety under 18 U.S. Code § 922(y)(3)(c)[25]

Each state has its own laws regarding who is allowed to own or possess firearms, and there are various state and federal permitting and background check requirements. Controversy continues over which classes of people, such as convicted felons, people with severe or violent mental illness,[26] and people on the federal no-fly list, should be excluded. Laws in these areas vary considerably, and enforcement is in flux.

Gun Control Act (codified at 18 U.S.C. § 922(g),(n),(d)[27][28]) makes it unlawful for certain categories of people to ship, transport, receive, or possess firearms or ammunition, to include any person:

The above categories are addressed on the ATF Firearms Transaction Record 4473 background check form[32]. According to the US Sentencing Commission, approximately 5,000 to 6,000 people a year are convicted of receiving or possessing a firearm against one of the prohibitions above[33].

^Bhagwat, A. (2010). The Myth of Rights: The Purposes and Limits of Constitutional Rights. New York: Oxford University Press. pp. 16–17. ISBN9780195377781. Justice Stevens begins his opinion by conceding Justice Scalia's point that the Second Amendment right is an 'individual' one, in the sense that '[s]urely it protects a right that can be enforced by individuals.' He concludes, however, that all of the historical context, and all of the evidence surrounding the drafting of the Second Amendment, supports the view that the Second Amendment protects only a right to keep and bear arms in the context of militia service.

^Bennett, R.; Solum, L. (2011). Constitutional originalism : A Debate. Ithaca, NY: Cornell University Press. p. 29. ISBN9780801447938. In both dissents, the clear implication is that if the purpose of the Second Amendment is militia—related, it follows that the amendment does not create a legal rule that protects an individual right to possess and carry fire arms outside the context of service in a state militia.

^Schultz, D.A. (2009). Encyclopedia of the United States Constitution. New York: Infobase Publishing. p. 201. ISBN9781438126777. Justice John Paul Stevens argued that the debate over the Second Amendment was not whether it protected an individual or collective right but, instead, over the scope of the right to bear arms.

^ ab18 U.S.C.§ 921(a)(20) ("The term 'crime punishable by imprisonment for a term exceeding one year' does not include—(A) any Federal or State offenses pertaining to antitrust violations, unfair trade practices, restraints of trade, or other similar offenses relating to the regulation of business practices, or (B) any State offense classified by the laws of the State as a misdemeanor and punishable by a term of imprisonment of two years or less...."); see also 18 U.S.C.§ 927 ("Effect on State law").